In an unusual move, the agency released a memo from FDA commissioner Robert M. Califf detailing a scientific dispute between Janet Woodcock, director of the agency’s drug evaluation division, and Ellis Unger, whose team reviewed Sarepta’s experimental drug.
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The approval comes almost five months after the Food and Drug Administration and a panel of outside advisers panned the drug, saying there was little evidence that it helped.
There was considerable disagreement within the FDA regarding Exondys 51’s approve-ability, but now that the approval is in hand, the company plans to begin providing this drug soon to patients who are amenable to it.
The confirmatory trial will be in that specific population with a primary endpoint based on the North Star Ambulatory Assessment, with a secondary endpoint of dystrophin levels as a percent of normal as determined by a tissue biopsy.
The indication is based on an increase in dystrophin in skeletal muscles observed in some patients treated with EXONDYS 51.
Sarepta is slated to submit a draft protocol for the upcoming trial in October with a final protocol submission due in April 2017. DMD occurs in approximately one out of every 3,600 male infants worldwide. Boys with the disease grow progressively weaker, becoming reliant on a wheelchair in their teens and dying in their 20s or 30s.
Under the accelerated approval provision, the FDA is requiring the maker of Exondys 51 – Sarepta Therapeutics of Cambridge, Mass. – to conduct a clinical trial to confirm that the drug helps patients. SunTrust Banks Inc. raised Sarepta Therapeutics to a “reduce” rating and increased their price target for the company from $4.00 to $48.00 in a research report on Tuesday.
Duchenne is the most common form of muscular dystrophy. “We are grateful to the many patients and investigators who take partd in EXONDYS 51’s clinical studies”.
But though the outcome was one many patients and their families had hoped and openly advocated for, it was a surprising twist after a fraught and drawn-out approval process, which lasted over a year and involved an unusual amount of open disagreement at the Food and Drug Administration.
McSherry of Pembroke, whose son Jett had been taking Sarepta’s drug in the clinical trial, said the FDA decision means “there’s no fear it can be taken away from him”.
Woodcock acknowledged the concerns in a statement, emphasizing that the drug would still have to undergo more trials to prove its efficacy.
DMD is a rare muscle-wasting disease caused by the inadequate production of dystrophin, a key protein necessary for building and maintaining muscle.
He added, however, that “serious shortcomings present in the eteplirsen development program should not be allowed to establish a broad precedent for therapeutic development in rare diseases”. The most frequently reported adverse effects of the drug include balance disorder and vomiting.
Speculation about the drug’s approval has run rife since the agency delayed the decision, which was expected months ago.
The analyst upgraded the stock to buy with a fair value of $65 and noted that Sarepta had also received a pediatric review voucher, limiting potential near-term dilution.
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The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices.
